Abstract: Introduction: The Toolbox for Research and Ex-ploration (TREX) is a NASA SSERVI (Solar System Exploration Research Virtual Institute) node. TREX (trex.psi.edu) aims to decrease risk to future missions, specifically to the Moon, the Martian moons, and near- Earth asteroids, by improving mission success and assuring the safety of astronauts, their instru-ments, and spacecraft. TREX studies will focus on characteristics of the fine grains that cover the surfac-es of these target bodies – their spectral characteristics and the potential resources (such as H2O) they may harbor. TREX studies are organized into four Themes: lab studies [1], Moon studies [2], small-bodies studies [3], and field work [4]). Here we describe one of several laboratory facilities to measure the spectral reflec-tance of fine-grained geologic materials. Background: Some of the only existing far UV (FUV, ~120-200 nm) measurements of the spectral reflectance of geologic materials were made decades ago [5, 6], indicating features of potential value in di-agnostic studies of composition. An expanding set of ultraviolet spectral reflectance measurements of solar system objects from the Hubble Space Telescope, Lu-nar Reconnaissance Orbiter, Cassini, Rosetta, and oth-ers has motivated a renewed interest.. For example, FUV spectra of Ceres obtained by HST suggest the presence of graphitized carbon [7], but few compara-tive datasets exist.
G. M. Holsclaw, M. M. Osterloo, T. Munsat, and A. R. Hendrix

Abstract: A simple method for measuring the second order diffraction efficiency in the vacuum ultraviolet (VUV) is described. Spectral reflectance of a mirror will be influenced by the second diffraction order, measured in a spectrophotometer system without filters. The second order diffraction efficiency can be calculated from the different spectral reflectance values. A deuterium lamp and a scintillated photomultiplier are used in the measurement system. The second order diffraction efficiency can be determined from 120nm to 165nm. The result of 0.00579±11.9% is obtained at 161nm.
Yi Qu, Shurong Wang, Zhenduo Zhang and Futian Li

Abstract: An evaluation of the behavior of three large cathode area photo-multiplier tubes, Hamamatsu R5912 Mod and R5912-02 Mod, and ETL9357 KFLB, was carried out both at room and cryogenic temperature, using a 405nm light source. The main electrical and optical features of the devices were studied; the obtained results were compared with the characteristics of the ETL9357 FLA tubes, used in the ICARUS experiment. Tubes were also studied as a function of the Earth's magnetic field and an evaluation of the quantum efficiency was made in the vacuum ultraviolet light region.
A. Falcone, R. Bertoni, F. Boffelli, M. Bonesini, T. Cervi, A. Menegolli, C. Montanari, M.C. Prata, A. Rappoldi, G.L. Raselli, M. Rossella, M. Spanu, M. Torti, A. Zani

Abstract: Studies on the linear and nonlinear optical properties of the BPO4 crystal have been carried out experimentally. The transmittance spectra in the vacuum-ultraviolet and near-infrared spectral regions were obtained, showing a transparency in the range from 134 to 4230 nm. The refractive indices were accurately measured at 12 wavelengths from 0.2537 to 1.530 μm and the Sellmeier equations constructed. Moreover, the nonlinear optical coefficients of the BPO4 crystal were measured with the Maker fringes technique, which gave a result of 𝑑36=0.76 pm/V
Xin Zhang, Lirong Wang, Shufeng Zhang, Guiling Wang, Sangen Zhao, Yong Zhu, Yicheng Wu, and Chuangtian Chen

Abstract: Photoluminescence (PL) spectra of anion-defective alumina single crystals and ultradisperse ceramics were measured under excitation in the vacuum ultraviolet (VUV) region. Emission bands in the experimental PL spectrum were identified using a developed technique to reconstruct spectra of luminescent dielectrics. A correspondence was found between the calculated and experimental PL spectra of α-Al2O3 single crystal. The PL spectrum of ultradisperse anion-defective alumina ceramic was calculated taking into account luminescence centers created by intrinsic and impurity defects. Bands in the experimental spectrum were identified based on it.
Vsevolod Semenovich Kortov, V.A. Pustovarov, Tatiana V. Shtang (Spiridonova), S. V. Zvonarev

Abstract: Application of π-multilayer technology is extended to high extinction coefficient materials, which is introduced into metal-dielectric filter design. Metal materials often have high extinction coefficients in far ultraviolet (FUV) region, so optical thickness of metal materials should be smaller than that of the dielectric material. A broadband FUV filter of 9-layer non-periodic Al/MgF2 multilayer was successfully designed and fabricated and it shows high reflectance in 140–180 nm, suppressed reflectance in 120–137 nm and 181–220 nm.
Xiao-Dong Wang, Bo Chen, Hai-Feng Wang, Fei He, Xin Zheng, Ling-Ping He, Bin Chen, Shi-Jie Liu, Zhong-Xu Cui, Xiao-Hu Yang and Yun-Peng Li

Abstract: Electrically-fused quartz glass, flame-fused quartz glass and plasma-fused quartz glass as well as synthetic fused silica samples were irradiated stepwise with a high energy Xe barrier discharge excimer lamp at 172 nm. VUV spectra were measured before and after every irradiation step. The results show that the VUV transmittance and the resistance against high energy radiation strongly depend on the quartz glass type, as well as on the thermal pretreatment of the quartz glass samples. In electrically-fused and plasma-fused quartz glass the VUV transmission decreases by the formation of oxygen deficiency and E' centres with absorption bands at 163 nm and 215 nm. Best irradiation resistance is found in synthetic fused silica and in thermally treated flame-fused quartz glass.
Photoluminescence spectra measured under excitation with a KrF excimer laser before and after irradiation indicate fundamental differences in the SiO2 network structure of the different quartz glass types. Whereas a poor radiation resistance correlates with a blue photoluminescence band at 390 nm, the photoluminescence of flame-fused quartz glass changes from blue to green by a thermal treatment which is correlated with a significant improvement of radiation resistance. A simplified model is presented referring to hydride and oxygen deficiency centres as precursors to colour centre formation in different types of quartz glass.
A Schreiber, B Kühn, E Arnold, F-J Schilling and H-D Witzke

Abstract: KBe2BO3F2 (KBBF) crystals have some extrinsic absorption in the deep-UV region around 150–160 nm and the reason was unknown. In this paper, undoped KBBF and Cu2+-doped KBBF crystals were grown for the investigation of the extrinsic deep-UV absorption behaviors. The samples were characterized by the transmission spectra, electron paramagnetic resonance (EPR) and photoluminescence spectra (PL). The impurity contents were measured by the inductively coupled plasma-atomic emission spectrometry (ICP-AES). Transmission spectra showed a red shift of about 5 nm in Cu2+-doped KBBF crystals compared with undoped ones. EPR signals only occurred in the spectra of Cu2+-doped KBBF crystals. Photoluminescence spectra showed emission bands at 416 nm and 441 nm which were identified as emission of Cu2+ions with an excitation wavelength of 380 nm. The fluorescence intensity of the Cu2+-doped samples is about 3–4 times higher than that of undoped ones. The above results reveal that Cu2+ ions are possible to enter into the crystal lattice and cause the deep-UV absorption.
Xiaolong Wanga, Lijuan Liua, Bo Xua, Xiaoyang Wanga, Chuangtian Chen

Abstract: A yttrium aluminum borate [YAl3(BO3)4] (YAB) crystal with UV cutoff wavelength of 165 nm is used as the nonlinear optical crystal for fourth harmonic generation. The fundamental frequency laser at 1064 nm from an Nd:YVO4 master oscillator power amplifier laser was frequency doubled to 532 nm. Using the type I phase-matching YAB crystal, a 5.05 W average power 266 nm UV laser was obtained at the pulse repetition frequency of 65 kHz, corresponding to the conversion efficiency of 12.3% from 532 to 266 nm. The experimental results show great potential for the application of using YAB as a nonlinear optical crystal to get high-power fourth harmonic generation.
Qiang Liu, Xingpeng Yan, Mali Gong, Hua Liu, Ge Zhang, and Ning Ye

Abstract: The photoluminescence properties of α-Zn2SiO4 nanoparticles formed in the SiO2 by means of ion implantation and subsequent 900 °C, 1 hour annealing in air atmosphere. Both X-ray diffraction, optical and photoluminescence (PL) spectra confirm the formation of willemite phase Zn2SiO4 in SiO2 matrices. The characteristic 2.4 eV PL band observed resembles the properties of classical Zn2SiO4:Mn phosphor, though no manganese were introduced into the samples. PL excitation spectra demonstrate the contribution of willemite and silica band states, thus suggesting interphase energy transfer mechanism. Thermal quenching and lifetimes of the luminescence observed provide the clues to figure out the nature of emission centres.
Anatoly Zatsepin, Evgeny Buntov, Vsevolod Kortov, Nikolai Gavrilov andHans-Joachim Fitting

Abstract: A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.
Akira Kuwahara, Makoto Matsui1, and Yoshiki Yamagiwa

Abstract: Development of antireflective coatings realized by thin film systems requires their characterization and optimization of their properties. Functional properties of such interference devices are determined by optical constants and thicknesses of the individual films and various defects taking place in these systems. In optics industry the characterization of the films is mostly performed in a relatively narrow spectral range using simple dispersion models and, moreover, the defects are not taken into account at all. This manner of characterization fails if applied to real-world non-ideal thin film systems because the measured data do not contain sufficient information about all the parameters describing the system including imperfections. Reliable characterization requires the following changes: extension of spectral range of measurements, combination of spectrophotometry and ellipsometry, utilization of physically correct dispersion models (Kramers-Kronig consistency, sum rules), inclusion of structural defects instrument imperfection into the models and simultaneous processing of all experimental data. This enables us to remove or reduce a correlation among the parameters searched so that correct and sufficiently precise determination of parameter values is achieved. Since the presence and properties of the defects are difficult to control independently by tuning of the deposition conditions, the optimization does not in general involve the elimination of defects. Instead they are taken into account in the design of the film systems. The outlined approach is demonstrated on the characterization and optimization of ultraviolet antireflective coating formed by double layer of Al2O3 and MgF2 deposited on fused silica
Daniel Franta; David Nečas; Ivan Ohlídal; Jiří Jankuj